A standard mixing faucet as described in German patent 3,330,156 has a faucet body that is mounted on the outside face of a support deck over a throughgoing hole therein and that is secured to this deck by a threaded stem extending through the hole and bearing on the opposite inside face of the deck. In addition hot- and cold-water feed lines extend through the hole to a valve housed in the faucet body and having hot- and cold-water inlet ports and a mixed-water outlet port. In a faucet with a removable spray head as described in German utility model 1,657,933, a mixed-water hose extends from the valve outlet port down through the hole where it forms a loop and then back up through the hole to where it is connected to the sprayer head.
Thus it is possible that the two supply lines, two different sections of the mixed-water hose, and the securing stem--five different elements--all have to go through the same hole in the deck. This is clearly a lot of structure to fit in a limited space. To accommodate this structure it is frequently made as small as possible, which can give problems with respect to strength and long-term service, and in any circumstances presents a considerable installation problem.